Four-speed-transmission gate device



p 1929- J. H. HUNT EI'AL 1,727,646

FOUR-SPEED TRANSMISSION GATE DEVICE Filed March 14, 1927 Patented Sept.10, 1929.

UNITED "STATES PATENT o -FicE.

JOHN H. HUNT AND THOMAS H. MILLAR, JR., OF.DETROIT,'MICHIGAN, ASSIGNORSTO GENERAL MOTORS CORPORATION, OF DETROIT, MICHIGAN, A CORPORATION OFDELAWARE.

FOUR-SPEED-TRANSMISSION GATE DEVICE.

Application filed March 14, 1927. Serial No. 175,240,

This invention relates to variable speed power transmission, andparticularly to a four forward speed transmission. In ac cordance withour invention we .makeuse of a novel gate device associated with thisshift lever.

An object of the invention ,is to render 7 easy, quick and certain theshift from low' speed transmission.

As a further object the invention provides for limiting the shifting totwo ranges, one range including all "forward speeds and the other rangeincluding reverse, low and second speeds. j

Other objects and advantages will be understood upon a reading of thefollowing specification and an examination of the accompanying drawing.I

In the drawing:

Figure l is a vertical longitudinal section through the top of a changespeed transmission housing. A

Figure 2 is a transverse section showing the operating lever and theforks.

Figure 3 shows in perspective the disassembled parts constituting theinterlock.

speed to reverse and vice versa in a plural ing three forks or threerails, there has been recognized a difliculty when moving the levertransversely. The hand on the knob of the lever cannot easily, andquickly detect the intermediate position wherein the lever engages themiddle fork which is ordinarily used to shift into low or second speed.To assist in locating this position and avoida shift from the high speedrail clear across into the reverse rail it is customary'to employ astop, which, unless released, stops the lever at the middle rail. Thisstop must be positively released before the leve shifted into thereverse rail or fork.

An arrangement of this kind operates very well for forward driving.There are times, however, when quick shifts must be made back and forthbetween low and reverse. Thedifliculty of locatingwith certainty the midposition when shifting from reverse into low makes it necessaryunderthese circumstances to lock the lever out of r may be reverseeach timeso that the stop may be used as a locater for the low speed position.These movements of the stop take time and render the shifting back andforth between low and reverse slow. I This serious objection ourinvention aims to overcome. I

Referring to the drawing, numeral 5 represents a portion, the projectingupper part of a transmission housing. This upper part 5 ofthe housing isshaped to seat the ball 7. The shift lever, by means of a ball joint, isthus given both a longitudinal movement for moving longitudinally anyone of the three forks 11, 13 and 15 with which its lower end may beengaged, and also atransverse movement for selectively engaging any oneof the three forks- As illustrated, these forks are mounted onrods 17,with which or upon which they move. The forks have projecting ends 11,13 and 15 to engage the slidable gears or'other movable parts to affectthe several gear ratios provided. The cap 19 and spring 21 areincidental to the'lever mounting and constituteno part of our invention.

Figure 3 illustrates an interlock designed v j for use with the leverandthe several forks. In transmissions of this general type us- Itincludes four plates. which may be very economically made by stamping. Asu'pportf with attaching flanges 25. In the flanges are apertures .27. Acover plate 29 has its ends 31 providedwith apertures 33 registeringwith apertures 27 through which apertures 27, and 33 and openings'in anenlarged part of the housing fastening means 37 are placed. The coverplate has a central opening shaped as shown to permit the lower end ofthe lever to move as required to make the several shifts provided for.An interlocking plate 39 has a rectangular opening 411 from the ends ofwhich extends longitudinal passages 43 to permit the movement of thelower end of the lever when shifting the forks. Plate 39 is alsoprovided with end notches 45. {A top plate 47 has a long slott9registering with the intermediate part of opening 41 and with i endsof cover plate 47 are turneddown as at 50 and engage notches 15 intheinterlocking plate. at? is also provided with slots 51 which are guidedby downturned lugs 53 in the cover plate 29. The downturned ends 50 andnotches ,render cover plate 47 and n terloc-king 'plateBS) relativelyimmovable.

, The two plates can have no longitudinal mentof its lower end movementowing to the engagement of their" versely by the lever 9 whenever thelever is moved transversely, owing to the engage against one side or theother of slot 419. j r i The three forks '11, '13 and .15 project intoopenings 11 of "the interlocking plate, as

shown in Figure 1. The transverse dimension of plateopening 41lSSUfiCiQDtly larger than the total width of the three forks as torender it possible toimove the interlocking plate and top platetransversely 1n either (he rection from a middle position. I is itsmiddle position/the slots ,49 and d3 lie over the middle fork and in itstransverse positions these slot-s overlie one or the other of the endforks '11 and 15. lVhen the lever is in its 1 middle pOSlblOl'l with theslots 19 and i3 over the middle fork the side forks are held from Vlongitudinal movement by engagement with the walls 61 of theinterlockingplate openmg. In this position, owing to the registra-.tion' of the slots with the middle fork,the lever may be movedlongitudinally to move that fork. -A forward movementof the knob endoftlielever corresponds to first speed shift and rearward movement ofthe lever-con responds to a second speed shift; If new the lever isreturned to its mid position longitudinally and moved transversely, theknob awa from the operator, the walls 61 hold both the IIllClCllQ forkand the reverse fork and slots49 and 43 permit the lever to be movedlongitudinally with a movement of the-third and fourth speed fork. Whenthe lever knob moved forwardly, a shift is made into third speed, andwhen moved backwardly a shiftis made into fourth speed. If

thelever is moved from its mid longitudinal position transversely to thereverse fork a rearward movementshifts that fork to make the gearengagement for driving in reverse,

": the middle fork and the high speed fork being locked by engagen'ientwith the walls61. ni

asinuch as the reverse fork needs to be moved 7 in but one directionfrom its mid position the opening in'the' cover plate is reduced inwidth on one side shown in Figure 3, thereby limiting the movement ofthe lever.

A plate 65, having an opening 67, is se cured to the housing by bolts69. The opposite walls ofthis opening 71 and 73 may be fork and theright fork (third and high).

In this positionthe upper projection 79 is so located as to engage wall73 and prevent the lever being moved transversely to engage 'fork ll forashift into reverse A rod 83 is mounted alongside thelever and atwitslower end is threaded into block 75. Atits upper end, adjacent the leverknob, the rod is provided with a hand grip 85 by, which the block may helifted against-the tension of spring 81. So moving the block raises pro:j'ection 79 sufficiently to permit the lever to be moved transversely toeffect engagement with the reverse fork. At-the same time, however,projection 77 islraised so that the third and fourth speedfork cannot beused,

owing to the engagement-of ,77 with wall 7 By this expedient thedisadvantage of the commonly employed releasable stop is avoided. Withthe block in its normalfull line position shifts may be made through thefour forward speeds using the middle and. the right fork without thepossibility of accidentally slippinginto reverse.v Should it benecessary to use reverse thedotted line position is used. \Vhen partsarein this position,

if a quick shiftinto low is, desired itmay be I made withoutfirstmovingtheblock 7 5 and with no possibility of getting the lever into thethirdand fourthspeed fork, as such a movement is rendered impossible bythe engagement'of the block withwal-l 71. Itmay be noted, also, thatthere is no. danger of accidentally shifting fromelow into. secondbecause'to do so would require a longitudinal reversing of the movementof the lever.

There are-thus -provided hy-the movable device two positions of action,one wherein shifts may be made in all four forward speeds and a secondposition wherein shifts may, be made utilizing the middle and reversefork only. Y Rapichcertain shifting is thus made possible, for allmovements which may be needed or desired by. a construction at oncesimple, easily applied and [economical to manufacture;

lVe claim: Y I

1. Ina gear shifting device, a lever having three transverse positionsforgearshifting, means ass'ociated. therewith includingco-operatingmemhers one of which is movable to two locations wher by, ineach of said loca tions, the intermediate position and one of the twoextreme positions only of said lever is available. i

2. In a gear shifting device, a lever having three transverse positionsfor gear shifting, means on said lever movable to two locations, meansassociated with said first mentioned means whereby in one location ofsaid first mentioned means the intermediate and one extreme positiononly of said lever is available and in another location the intermediateand the other extreme position only is available.

3. In a change speed transmission, three shifting members mounted forlongitudinal movement, operating means to selectively engage saidshifting members and move the same, movable mechanism associated therewith and a fixed abutment associated with said movable mechanism torestrict the operation of said operating means to selected pairs of saidshifting members.

4. The invention defined by claim 3, each of said pairs including theintermediately positioned member.

5. In a gear shifting mechanism, a housing, a lever therein for shiftinggearing, abutments in said housing, a member movable on said lever toengage the one or the other of said abutments whereby the lever may berestrained from shifting the mechanism into reverse, or from shiftingthe mechanism into high speed.

6. In a gear shifting mechanism, a'housing, a lever projecting into saidhousing, a plate carried by said housing and having abutments in acommon plane on opposite sides of said lever, a block slidable on saidlever having an upper projection on one side to engage with one of saidabutments in one position of the block, and a lower projection on theother side to engage the other abutment in a second position of theblock, and means to move the block.

7. In a gear'shifting mechanism, a lever movable for shifting saidmechanism for driving in forward speeds and in reverse, a fixedabutment, locking means movable to a plurality of positions ofengagement with said abutment to prevent a shifting into reverse 1n oneof said positions and to prevent a shifting into high speed in anotherof said positions.

8. In combination, change speed transmission, a plurality of movablemembers operably related to said transmission to effect a plurality ofspeed ratios including a low speed ratio, a shift lever movable toindividually engage said members, movable means controlling said levermovements, and movable into two positions, in each of which positionsthe lever has a definite range of movement, an abutment engaged by saidmovable means in each position, each range including a lever positionwherein it engages the member operable to give the low speed ratio.

9. The invention defined by claim 8, one of said ranges also including alever position wherein it may engage the member operable to give reversedrive, vbut which range is limlted to exclude that position of the leverwherein it operates the member controlling,

high speed, the lever in its other range operable upon the high speedcontrolling member but inoperable upon the reverse controlling membe IIn testimony whereof we aifix our signa

